unset $PHP_AUTH_USER

Hi all, I am new to PHP. I were practise with authentication with PHP. My problem is it only authenticates me the first time, then $PHP_AUTH_USER keeps unchanged. I tried to unset the $PHP_AUTH_USER as in the following script, and I could see its value cleared, but when I reload the the php file, the authentication box still not display. Thanks for your help, Dt ----------------------------- <?php function authenticate() { header("WWW-Authenticate: Basic realm=\"Sample\""); header("HTTP/1.0 401 Unauthorized"); echo "You are not authorized to use this system"; exit; } if( !isset($PHP_AUTH_USER) ) { authenticate(); } else { print "Before unset: $PHP_AUTH_USER<BR>"; unset($PHP_AUTH_USER); unset($PHP_AUTH_PW); unset($PHP_AUTH_TYPE); print "After unset: $PHP_AUTH_USER<BR>"; print "End"; } ?> _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com